


Feelin' the love.

by HanaNaraku



Category: Undertale (Video Game)
Genre: AU, Alternate Universe - Underswap, Ecto private parts, Fontcest, Incest, M/M, PapySans, Skeleheat, Underswap Papyrus, Underswap Sans
Language: English
Status: Completed
Published: 2016-01-09
Updated: 2016-01-09
Packaged: 2018-05-12 19:01:24
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,909
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5677042
Author URL: https://archiveofourown.org/users/HanaNaraku/pseuds/HanaNaraku
Summary: <blockquote class="userstuff">
              <p>Sans comes home from Undyne's with a new outfit and wants to show his brother how cute it is.<br/>However his brother unable to hold himself back (and the fact he is half asleep) causes the situation to escalate...</p>
            </blockquote>





	Feelin' the love.

**Author's Note:**

> Can't think of titles...  
> But I hope you enjoy, its supposed to be Underswap characters.  
> Just so y'know I feel that whilst Sans is naïve to some things, he isn't as innocent as his appearance lets on. He loves taking advantage of his cuteness and his brother trying to hold back but obviously isn't too cruel and doesn't do anything to the extreme. But this time what if he can't hold back?

Papyrus was sat on the couch. His arms placed at the back of his head. The house was quiet as Sans was with Alphys training. Papyrus took this small peaceful time to take a nap before work.

Sans on the other hand was in Undyne's lab, having a hot cocoa.

"I found a cute outfit the other day Sans and I figured that since Papyrus is into anime, you might want to cosplay it?"

"Y- yeah! that sounds like fun" Sans smiled before taking a sip from his drink, filling his cheeks with a blue blush "Papy hasn't been too smiley lately" Sans sighed.

"I think adjusting to this new world must be tiring" Undyne said, "Were all trying to find stable jobs y'know?"

Sans nodded and looked down at his hot cocoa, "Maybe I should get a job?"

"Oh um technically you have one." Undyne attempting to lie, "You work with Alpys and she does those fitness classes"

"Yeah I guess so" Sans rubbed the back of his head.

"Let me grab that outfit for you" Undyne said. She got up and walked into another room, rumbling could be heard and the occasional crash of a falling object.

Sans put his empty cup down and stood up as Undyne came back into the room.

"H-here!" Undyne said giving him a box that was wrapped with a white paper and red ribbon.

"You can try it when you get home yeah?" Undyne smiled, she was excited for the little guy, after all she couldn't help but ship the cute skelebros.

Sans took the box and gently shook it up and down, a bell was heard in the box. Sans could only imagine what a cute outift this could be.

"Thank you Undyne" Sans smiled. Undyne rubbed his head before the two walked towards the door.

"I should leave before it gets too dark" Sans said.

"Alright be safe!" Undyne opened the door, the sun was setting. Papyrus was due to go to work soon, making the small skeleton determined to get home quick.

With haste he ran towards his home, not taking anyone's looks into consideration but being safe when it came to crossing roads. He wasn't as daft as everyone thought nor innocent. To be honest Sans enjoyed having the upper hand when it came to being cute, since no one was wiser to his shennanigans especially his older brother of whom was a joy to tease.

He opened the door and saw his brother asleep on the couch, he quietly walked up the stairs, avoiding the creaky floorboards and went into his room.

He placed the box on the bed and took off the ribbon and wrapping.

It was a light pink school uniform. This was kinda normal to Sans now but their was a few additonal objects. One being a collar with a bell on it and cat ears. For a while Sans has been practicing a cat tail with his magic but more often than not it wouldn't appear for long. So he never showed Papyrus this skill but hopefully wearing the outfit and collar... will inspire him?

He put the outfit on and looked at it in the mirror. It looked cute or so he thought.

"Maybe Papy would like it too?" Sans mumbled to himself, before a menacing smirk smoothered his face. He opened his door and walked down the stairs, his brother was still asleep so now was his chance.

Papyrus felt tugging on his jumper, he tried to push whatever it was out the way but the tugging became more tough. Wearily he opened his eyes.

"C'mon bro you've got work soon"

Papyrus looked at his watch, unfortunately he was right. He sighed and sat upright Sans was a little disappointed that his brother hadn't even noticed the outfit he was wearing.

Papyrus stretch his arms resulting in a few cracking popping sounds, when his body relaxed again he glanced over at his brother.

"You okay Papy?" Sans asked with a grin.

"What are you wearing?" Papyrus said nervously.

"I got it from Undyne!" Sans stood up and did a little turn to show it off, "Its cute"

Papyrus' expression was priceless, full of blush, confusion and pure lust. Sans was stood with a happy smile whereas Papyrus still half asleep wasn't too sure with what he should do.

However Sans came back to Papyrus and sat next to him on the couch. He put his hand on his brothers knee and looked up at him.

"Papy?"

Papyrus grabbed his brothers hand and pulled him onto his lap, he grabbed the collar and looked in his brothers eyes. Sans felt so nervous at his intense glare, maybe he had gone to far.

"I'll go change if you want..." Sans pouted, turning his head. Though Papyrus quickly pulled him back and clinked his mouth on his brothers. A warm tongue seemed to form and stroked his mouth in an attempt to open it, Sans complied and let his brother in. Papyrus used his tongue to gently rub the top his mouth.

Sans gripped his brothers jumper whilst Papyrus moved his brothers legs so that they were on his hip bones, he grabbed Sans' back and pulled him closer. As Papyrus is still carassing his brothers soft spot, Sans arched back a little as he was drowning in pleasure.

Papyrus pulled back and took a breath, Sans fell back onto his brother and rested his head on his brothers chest as he too panted for air. Papyrus looked at his watch again it was time for him to go, he didn't want to as his brother looked bright blue with arousal.

"By.. the way.. Sans.." Papyrus panted, "You look really cute"

Sans blushed even more brightly, his grip on his brothers jumped still tight.

"Th- thank you"

"I love you bro" Papyrus hugged his brother, resting his head on the little ones shoulder.

"I love you too" Sans smiled though Papyrus wasn't able to see, he could certainly feel his body wanting to devour his brother right here and now, still he held those feelings back the best he could. Not wanting to make his brother feel uncomfortable.

"Papy... is what I feel about you wrong..?" Sans asked out of the blue, making Papyrus pull back and look at his brother. Sans also pulled away from the embrace to see his brother.

"What do you mean?" Papyrus asked.

"I want to make you feel... good" Sans mumbled, he was embarrased to say out aloud but it was true, "I mean I know you love to eat my tacos cause they seem to make you happy but... in anime... when they are in love they kiss each other and do some weird things together" Sans looked his brother in the eye, "Even if they are related!" his eyes seemingly bright with passion, Papyrus didn't want to put his brother down and upset him but this could all be a misunderstanding.

Papyrus sighed and rubbed the back of his neck, "Oh Sans... our feelings for each other aren't wrong as such. But they aren't exactly smiled upon. Anime is a whole other subject to be honest but if you don't feel like its wrong then I don't mind" he winked.

"Really?" Sans' eyes glowed a bright blue and seemed to fill with hearts.

"But thats to say... are you sure you can handle it? you looked done after that kiss" Papyrus stuck his tongue out.

"Y- yeah!" Sans pouted, "It was just such a surprise!"

"Heh. So was that outfit" Papyrus chuckled.

Sans smiled, resting his head on his brothers chest again for comfort. It was always relaxing to the small skeleton as he felt safety being close to Papyrus. Looking up at Papyrus he pushed him down on the couch and sat upright so Papy could see his just how cute he could be.

Papyrus was surprised to be laying down on the couch with his brother resting on him but damn was that outfit sexy. As Sans put his hands up his brothers chest the bell clinked, he rubbed his rib bones, massaging them in all the soft spots.

It was all happening so suddenly and fast as Papyrus felt his eye glow bright. He moved his hands over to the top of Sans' body and felt the back of his spine, he rubbed it as gently as he could considering the treatment he was getting. Sans unlike his brother couldn't hold back his moans for too long.

"Mmm Papy..."

Papyrus leaned up towards his brothers neck and kissed it whilst still continuing to rub his spine. Sans couldn't keep up on his end and had to hold onto Papyrus' jumper. Papyrus taking advantage of his brother being so close had moved his hands towards his little brothers ribs and started to rub them, Papyrus knew that Sans' had a very weak g-spot on his ribs and wanting to please his little brother and give him a good time, he had to find it.

"Papy..." Sans whispered. He then grabbed his brothers hand and put it close to his soul before winicing in anticipation.

Papyrus knowing why he did this started to rub the ribs surrounding his soul. Sans moans got increasingly louder and soon Papyrus felt it. Not only was it chilled but wet.

"Can I?" Papyrus whispered into Sans' ear.

Sans nodded and the two pulled away for a moment. Sitting back upright and with Sans now the one lying down Papyrus' cold boney fingers pulled off the skirt and the once white lacey panties off revealing Sans' errect penis.

Sans looked away, his face bright blue with blush. Papyrus took a hold of the chilled penis with both of his hands, looking over at his brother with a smirk he started to slowly pump up and down the member gliding gently underneath and reaching from the base ro right below the head. Sans' moaned in pleasure, grasping whatever he could hold. Without being fully aware of it he spread his legs a little wider.

"Papy... hnnn~"

Papyrus relishing at the sight of his younger brother being lost in ectasy removed one of his hands and stroked his brothers head.

"I love you so much..." he said.

"I... love you.. too!" Sans said almost in a yell, his tongue was lit up to a bright blue, his eyes glowing so bright and filled with hearts making Papyrus' own soul flutter with joy.

Moving his attention back to his brothers pelvic area, he leaned in close at the dripping penis and licked the top as though to test his brothers reaction. Hearing a moan, made him feel confident to continue.

His spare hand being gripped by his brother and the other now moving to keep his balance on the sofa. Papyrus inched his face closer to his brothers member and gently with his tongue licking away all the cum that seemingly flowed out.

"Mmmm...! Papyy~" Sans moaned again his grip tightening. As he was getting licked he rolled back his eyes, his tongue dripping a light blue ecto salavia.

Feeling the heat, he began to run on instinct and sped up the pace of his tongue, making Sans moan louder, he went closer to the edge. Feeling his grip on this sweet reality loosen as an new sensation built from him.

"Pappyy... I- I...! nyaaaa~" he purred as he reached his first climax, covering his brothers warm, orange tongue in ecto cum. Pulling back a line of emerald was present though Papyrus focused his gaze on his brother has he closed his mouth and swallows a smirk plastered on his face.

Sans was biting on of his fingers, still panting and oozing with blue salavia. Papyrus took this time to remove his now stained hoody revealing his black tank top and all of his ribs. Sans glanced down at his brother and slowly sat upright with Papyrus giving him a hand.

Sans looked up at his brother face, his eyes still a bright blue. He rubbed over his ribs, Papyrus winced as his younger brothers hands were surprisingly cold. Sans then pulled up the tank top a little so he could get to his soul and smoothly grabbed it.

Papyrus put his hands back to stay upright but watched his little brothers every move.

"Can... can I kiss it?" Sans asked.

Papyrus nodded but looked away, he wasn't usually concious about this kind of thing but his soul being touched was sensitive.

Sans now holding the soul close gave it a kiss and compasionately held it close to his own. The two souls fluttered when near one another. Sans had wondered what happened if both souls were together?

Without hesitiation he placed it close to his own, the two swirled with one another and glowed passionately. Papyrus desperately held back a moan as it felt so natural for them to be together. Sans unable to hold much back also moaned but as the souls were lifted above the pair, he lost in a daze wanted to pull back his own brothers shorts and give him something to enjoy.

"S- sans~" Papyrus' cheeks flushed a bright orange gazed over at his brother of whom was fixated on his visible, errect penis, was now pulling his shorts down. Not doing much to stop it, he helped to pull them down, revealing his bright orange cock.

Sans wanted to try what his brother had done to him. So with one hand he gripped the middle of his penis and moved it up and down and occasionally squeezing it at the top, causing cum to come out. When their was enough Sans moved in close and licked the very top to get a taste.

"Soo good Sanss~" Papyrus hissed, almost giving his brother a sign of approval. He pushed his brothers head further down, Sans accepting the challenge took it well and massaged the cock with his slender blue tongue. What was even better was that the bell still on his neck would occasionally catch on the cock causing slight scratching but that made it more enjoyable for the taller skeleton as he relished every moment.

"S- Saaanss!" Papyrus reached a climax, Sans seemingly took it well and lifted up his head and swallowed the cum and licked his fingers as they too had some on them. Sans on top had his head above his brothers and leaned down to kiss him.

Papyrus rubbed his brothers back, looking him in the eyes, his brother looking back. When they pulled away, Papyrus had a feel for his brother cock as it too had climaxed and was oozing with blue ecto cum.

"I love you..." Sans moaned as his brother stroked off the cum on his brothers cock.

"I love you more~"

The two fell back into a pattern and continued to fuck one another until it was midnight. Exhausted the little skeleton was resting on his brothers chest, Papyrus was lying down his hands firmly on the small skeletons back.

When he took a moment to glance up, he noticed the two souls still bound together, peacefully enjoying one anothers presence in what seemed to be pure bliss. Though it seemed wrong, he pulled his away from the other and placed it back in his chest, Sans' seemed to follow for a moment before returning to his place.

The two sighed in unison.

Sans looked at his brother again, smiling. though it was cute short when he felt something pop from the area above his butt.

Wide eyed he got up and looked a bright smile plastered on his face.

"I did it!" he said giddly.

"You did what?" Papyrus asked, nervously. He wasn't sure he could go again.

Sans got up and twirled around, revealing a blue cat tail.

"I've been practicing for ages! and its here" he giggled, before moving it up and down.

Papyrus smiled and chuckled at his brother. That damn otaku...

"I gotta say Sans... you know some moves"

"Eh...?" Sans blushed again, "Well... Undyne did show me this one anime..." Sans glanced at his brother, of whom was rubbing his head.

"Bu- but don't tell her that I told you!" rushing over to his brother he sat back on his chest, "Please!"

"Heh. Alright" Papyrus said, though he looked crossed, he was actually happy for his brother to know such techniques. "But you can't do those things with anyone else okay?"

"Okay!" Sans smiled again, his tail occasionally hitting his brothers legs. 

Papyrus noticing his brother was yawning so he got up, put his shorts back on and took him up to his room. After placing him on the bed and getting him changed out of those clothes and into clean pajamas tucked him into the bed.

"Pappyy don't leave me" Sans pouted, reaching out his hand.

"Well... just for tonight..." Papyrus felt overjoyed at such a wonderful day, sure he missed work and was likely to be fired but he didn't care. Spending time with Sans was rare these days and this was just a occassion that he took advantage off and throughly enjoyed it. To his relief Sans was also very happy.

He climbed into the bed and held his brother tight. Both souls being close once more.

"I love you Sans..." Papyrus yawned before closing his eyes.

"I love you more~" Sans smiled, before also closing his eyes.


End file.
